Cutting tool



July 31, 1928. 1,679,049

s. T. NELSON Y CUTTING TOOL Filed April 5, 1922 mumW Patented July 31,1928.

UNITED STATES 1,679,049 PATENT OFFICE.

svmr T. NELsoiI, or'onlroao'o, rumors, assrenoa Tosonmv'AN' MACHINERYcom- 4 PANY; CORPORATION OFMASSAGHUSETTS.

CUTTING Toot.

Application filed-April 5, 1922. Serial No. 549,858.

My invention relates to cutting tools, and more particularly to cutterbits for use 1n the cutter chains of mining machlnes.

In coal mining machines of the chain cutter type, it is customary toemploy a series of cutter bits, i. e. sharpened cutting elements, whichare mounted in the several links of the cutter chain and so staggeredrelative to each 1 otherin the chain that several bits making up agroupcut a path somewhat wider than the thickness of the cutter bar, each bitof the groups cutting away a differentpath through the'coa'l: Such bitshave heretofore been largely formed by a hammering process, either byhand or by light power hammers. It has been found in practice that thebits so formed are not uniform; that-their shaping is so irregular thatthere is almost-as' much wedgingas cutting; that by reason of thedifferences in thickness at the points, wear is much more on some bitsthan others; and that no conception of the desirability of providing aproper clearance for the bit to the rearof the cutting portion thereofhas apparently been had.

The object of my invention is to provide an improved, durable, uniform,clean 'cutting cutter bit and particularly to provide an improved bit inwhich the supportlng surface for the cutting portion of the bit shall besuitably relieved in such manner as to provide for the elimination offriction between the supporting surfaces and the sides of the cutandfor' the ready escape; of particles of material frombetween the sidesof the bit and the material cut;

In the accompanying drawings I have shown for purpose's'of illustrationone form which myinvention may assume in practice.

In these drawings Fig. 1 is a side-elevationof the" illustrative form ofmy improved bit ina position corresponding to thatwhic'h itwould occupy'in a chain links I Fig. 2*is a front iewthereof:

Fig. 3 is a rear-view thereof.-

' F ig.;4 is a section on the line of- Fig. 1: i

Fig." 5 a section on the lihe *5 =5 of Flo; 1: v

ii'g. 6*isa sectiono'n plane parallel to the plane of line 4-4 ofFig. 1. Y

My improved-bit is preferably made by or) a rolling" process, althoughother methods could be employed provided the requisite care wereexercised. However,.by the use of suitable stationarykand' moving diesit has been found possible to produce my im-, I

proved bits in large quantities and in a very rapid manner.

In the illustrative embodiment of my invention it will be noted'thatupon theout'er end of a rectangular shank 1-, a cutting point 2- isformed. This cutting point presents,

grees. This gives to the'bitan angle of approximately 30 degrees; I V Inow desireto call especial attention to the conformation of the portionof the point 2- which supports the surface 3. From Fig."

5 it will be noted that this portionis at no point in any transverseplane parall'elto the in the form of my bit selectedfor illustrae pathof movelnent'of the' bit of awidth equal to the width'of the face 3and'so that while the face 3 is fully supported, yet due to the fact,that theysides 7 and E5 of the point 2 recede or fall. away towardseachother from the surface 3, even though conslderable wearmg of thecorners, '1. e; the material at the lines of juncture 9 and- 10 betweenthe surface 3 and'the surfaces 7 and'S, oceurs,*there willbe no materialloss ofpower due to the dragging of the'surfa'ces' 7 and 8 upon thesides of the groove or the development E of friction by reason of thetendency for particles of material to pack between thesides 7 and 8 andthe sides ofthe groove; The recedingfeatureabove referred to will bemore: easily seen. by having reference to Fig; 5which is ahorizontaltransverse'section on line 5 5 of' Fig. 1L Twopara'llle'llines 7 and S lying'inthe" same plane as indicated line" 5 5 in Fig. 1',pass adjacent'the sides of the face 3, hence'itrac'es'of the surfaces 7andS-ofthe cutting portion recede from one or the other of two parallellines 7 and 8'. In other words the cutting portion of the bit hasclearance on both sides during cutting. I

These bits are now believed to be best formed by a grooved rolling dieor by movement of the bit bodily past a rotatable grooved die, the diebeing grooved to a shape to lit the outlines, the top and sides, of Fig.4c, and the relative path of die to bit or bit to die being eitherstraight or curved, but in the general direction of the double endedarrow in Fig. 1. The die may be either slightly concave as to its sidewalls, in which event, as shown, the amount of stock supporting thepoint will be larger, or may have straight sides which would simplyproduce plane sides 7 and 8. In either event, due to the angle betweenthe relative path of the bit and die and the path of the bit whencutting, the cutting face 3 of the bit will be supported by graduallytapering material and ease of cutting insured. It will here be notedthat the intersection of the surfaces 7 and 8 produced will be a. lineso disposed that a straight line passing through any two adjacentpointstherein will make an angle with a line perpendicular to the length ofthe shank. Due to the fact that a grooved bit-forming roller is used,the traces of the bounding surfaces .7 and 8 on a t 'ansvel'se plane,such as shown in Fig. 4, would be the same as the traces of saidsurfaces on a second transverse plane, which planes have the samerelation to said surfaces. Thus if the roller is made to travel inastraight path during forming of the bit, the two planes would be"parallel thereby causing them to have the same relation to thesurfaces. If the roller travels in a curved path during forming, thesurfaces would accordingly be curved and the two transverse planes inorder to have the same relation to the sides would be normal thereto orextend radially from the center of curvature of the curved path throughwhich the roller travels. In this latter case the planes would not beparallel. These latter planes could also be equally odset from normaland still allow the required similarity between the traces on therespective planes. Any combined rectilinear and curvilinear movement ofthe roller or irregular movement thereof will be met by the aboverequirements or their equivalent. In any event the cross sectional areaof the cutting portion at any two points will be the same regardless ofthe roller movement, due to the use of a grooved roller. It is to beunderstood that if the edge 2 curves from the point 5 or someintermediate point due to the fact that the metal of the bit blank didnot fill out the roller groove during initial engagement of the rollerwith the blank, then the surfaces 7 and 8, when finished,

would have traces at least a portion of which are the same in theplanes. The slight swell at the front of the bit at, and just above thejuncture between the point 2 and the shank 1, results from the fact thatthe die groove is slightly wider at its widest point than the stock itworks and as the stock accumulates in front of the die it spreadsdownwardly into the space between the stock and the sides of the groove.This results in a very rugged construction at the juncture of shank andpoint. It is of course to be understood that instead of the cuttingportion tern'iinating-in a point it may terminate in a relativelystraight cutting edge to form what is commonly known as a chisel pointbit.

lVhile I have in this application specifically described one form whichmy invention may assume in practice, it will be under stood that thisform of the same is shown for purposes of illustration and that theinvention may be modified and embodied in various other forms Withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire by Letters Patent is:

1. As an article of manufacture, a coal mining machine cutter bitcomprising a single homogeneous piece of material affording a shankterminating in a cuttingportion having a cutting face, the materialsupporting said face presenting bounding surfaces whose traces on planeparallel to the path of instantaneous travel .of-the bit but pertosecure pendicular to its plane of instantaneous movement recede fromoneor the other of two parallel lines lying in said hrst mentioned planeand passlng adyacent the sides of the cutting face, and also havingtraces,

at least a portion of which are the same, on any two planes having thesame relation with respect to said surfaces, said surfaces beingsymmetrically disposed with respect to the longitudinal axis of saidshank.

2. As an article of manufacture, a coal mining machine cutter bit forgedfrom a single homogeneous piece of material afford ing a shankterminating in a cutting portion having an inclined-cutting face, thematerial supporting said face presenting bounding surfaces whose traceson a plane parallel to the path of instantaneous travel of the bit butperpendicular to its plane of instantaneous movement recede from one orthe other of two parallel lines lying in said first mentioned plane andpassing adjacent the sides of the cuttingv face, and also having tracesat least a portion of which are the same, on any two planes having thesame relation with respect to said surfaces.

3. As an article of manufacture, a coal mining machine cutter bit forgedfrom a single homogeneous piece of material afiordill) ing a shankterminating in a cutting portion having a cutting face, the materialsupporting said face presenting bounding surfaces whose traces on aplane parallel to the path of instantaneous travel of the bit butperpendicular to its plane of instantaneous move ment recede from one orthe other of two parallel lines lying in said first mentioned plane andpassing adjacent the sides of the cutting face, and also having traces,a portion of which are the same, on any two transverse planes which arenormal to said surfaces. I

l. As an article of manufacture, a coal mining machine cutter bit forgedfrom a single homogeneous piece of material affording a shankterminating in a cutting portion having a cutting face, the materialsupporting said face presenting bounding surfaces whose traces on aplane parallel to the path of instantaneous travel of the bit butperpendicular to its plane of instantaneous move mentrecede from one orthe other of two parallel lines lying in said first mentioned plane andpassing adjacent the sides of the cutting face, and also having traces,at least a portion of which are the same, on any two transverse planeswhich are parallel to each other.

5. As an article of manufacture, a coal mining machine cutter bit forgedfrom a single homogeneous piece of material affording a shank and acutting portion terminating in a wedge-like cutting face symmetricallydisposed with respect to the longitudinal aXis of the shank, said bit,at points adjacent the juncture between said portion and shank, beingwider than the width of the shank proper, said portion presentingbounding surfaces whose traces on a plane parallel to the path ofinstantaneous travel of the bit but perpendicular to its plane ofinstantaneous movement recede from one or the other of two parallellines lying in said first mentioned plane and passing adjacent the sidesof the cutting face, and also having traces a part of which are the sameon two transverse planes which travel of the bit but perpendicular toits plane of instantaneous movement recede from one or the other of twoparallel lines lying in said -first mentioned plane and passing adjacentthe sides of the cutting face, and when out by any two planes having thesame relation with respect thereto have traces, at least a portion ofwhich are the same.

7. A cutter bit forged from a single piece of homogeneous materialadapted for use with a mining machine cutter chain comprising a cuttingportion having a cutting face symmetrically disposed with respect to thelongitudinal axis of the shank and provided with clearance, said portionhaving a plurality of cross sections which are sub stantially identicalwhen taken so as, to have the same relation with respect to the boundingsurfaces of said portion.

8. A cutter bit having a shank terminating in a cutting point which hasan inclined cutting face symmetrically disposed with respect to thelongitudinal axis of the shank tapering laterally from its point ofjuncture with the shank to its outer end supported by a portion of saidpoint which is bounded by a pair of surfaces the elements of which areparallel and make angles with the length of the shank, said surfacesdiverging from a relatively narrow surface making an angle .with thefirst mentioned surface to their juncture with said cutting face andwith the sides of the shank.

In testimony whereof I affix my signature. 7

svnu T. NELSON.

